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United States Patent |
5,680,122
|
Mio
|
October 21, 1997
|
Platoon running control system
Abstract
A platoon running control system which is able to recognize the position of
a vehicle within a platoon and to appropriately respond to a change, for
example, when another vehicle leaving the platoon. If the vehicle is not
in a platoon running mode, a communication control ECU assigns an ID=1 to
the vehicle, and a vehicle control ECU operates the vehicle in an
auto-drive mode based on a signal such as from a magnetic sensor or a CCD
camera. During platoon-running mode, a light receiver receives data
including ID information from a preceding vehicle, and the controlled
vehicle is assigned an ID according to a rule in which the ID of the
vehicle=ID of the preceding vehicle+1. Then, the vehicle starts platoon
running using data from the preceding vehicle. When the system received
information that the preceding vehicle will leave the platoon,
platoon-leaving data is transmitted to the vehicle, which then transmits
such data to the following vehicle. The vehicle changes its ID to 1 when
it does not receive any more data from the preceding vehicle. In a case
where its ID has been changed to 1 from 3 or greater, the vehicle
accelerates so as to re-form the platoon.
Inventors:
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Mio; Masahiro (Susono, JP)
|
Assignee:
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Toyota Jidosha Kabushiki Kaisha (Toyota, JP)
|
Appl. No.:
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694382 |
Filed:
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August 8, 1996 |
Foreign Application Priority Data
Current U.S. Class: |
340/932; 180/167; 340/436; 340/902; 340/904 |
Intern'l Class: |
G08G 001/00; G08G 001/096 |
Field of Search: |
340/932,904,903,902,901,436
180/267,167
|
References Cited
U.S. Patent Documents
4621705 | Nov., 1986 | Etoh | 340/904.
|
4706086 | Nov., 1987 | Panizza | 340/902.
|
4934477 | Jun., 1990 | Dai | 340/436.
|
5091726 | Feb., 1992 | Shyu | 340/904.
|
5249027 | Sep., 1993 | Mathur et al. | 356/1.
|
5289183 | Feb., 1994 | Hassett et al. | 340/905.
|
5295551 | Mar., 1994 | Sukonick | 180/167.
|
5331561 | Jul., 1994 | Barrett et al. | 364/447.
|
5369591 | Nov., 1994 | Broxmeyer | 180/167.
|
5416711 | May., 1995 | Gran et al. | 364/436.
|
5424726 | Jun., 1995 | Beymer | 340/932.
|
Foreign Patent Documents |
62-53529 | Mar., 1987 | JP.
| |
5-170008 | Jul., 1993 | JP.
| |
6-262988 | Sep., 1994 | JP.
| |
Primary Examiner: Hofsass; Jeffery
Assistant Examiner: Tweel, Jr.; John
Attorney, Agent or Firm: Kenyon & Kenyon
Claims
What is claimed is:
1. A running control system for controlling platoon-running installed on a
vehicle, the system comprising:
(a) receiving means for receiving data which is transmitted from a
preceding vehicle;
(b) transmitting means for transmitting data to a following vehicle;
(c) identification code setting means for assigning to the vehicle an
identification code, wherein the identification code setting means either
assigns a code indicating that the vehicle is a leading vehicle if the
receiving means has not received any data from any preceding vehicle, or
an identification code obtained by converting an identification code of a
preceding vehicle contained in data received from the preceding vehicle
according to a predetermined rule, if the receiving means has received
data from the preceding vehicle; and
(d) control means for controlling operation of the vehicle based on the
identification code of the vehicle assigned by the identification code
setting means,
wherein the identification code indicates a position of the vehicle within
a platoon.
2. The running control system according to claim 1, wherein the
identification code indicative of the leading vehicle is 1, and the
predetermined rule is expressed by the following expression:
Identification code of the vehicle=Identification code of the preceding
vehicle+1.
3.
3. The running control system according to claim 1, wherein the control
means controls the vehicle on the basis of the data from the preceding
vehicle received by the receiving means, if the identification code of the
vehicle is not the identification code indicative of the leading vehicle.
4. The running control system according to claim 1, wherein the control
means controls the vehicle to accelerate and catch up with a currently
preceding vehicle if a present identification code of the vehicle is
indicative of a leading vehicle and a previous identification of the
vehicle indicated that the vehicle was previously running in the third or
later position within the platoon.
5. The running control system according to claim 1, further comprising:
(e) communication control means for superimposing platoon-leading
information onto data to be transmitted to the following vehicle.
6. The running control system according to claim 1, wherein the
identification code setting means also assigns to the vehicle the
identification code indicative of the leading vehicle, if the receiving
means has received platoon-leaving information from the preceding vehicle.
7. The running control system according to claim 1, wherein the control
means determines whether or not a preceding vehicle which has left the
platoon was the leading vehicle based on a previous identification code of
the vehicle, and controls the vehicle to accelerate and catch up with a
currently preceding vehicle if the vehicle which has left the platoon was
not the leading vehicle.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a platoon running control system, and more
particularly to a system for controlling a vehicle running in a platoon
while recognizing its position within the platoon.
2. Description of the Prior Art
When vehicles travel on an expressway, it is occasionally desirable for a
vehicle to follow a preceding vehicle in view of reducing the driving
operation, and therefore a plurality of vehicles may sometimes run in a
platoon (The running state in which a plurality of vehicles run in a
platoon is hereinafter called "platoon running"). It has been proposed to
actively utilize such platoon running in auto-driving of vehicles.
For example, Japanese Patent Laid-Open No. Hei 5-170008 discloses a system,
installed on a vehicle, which receives control operation data, running
state data, vehicle specifications, and so on from a preceding vehicle and
calculates a control amount for the vehicle based on the received data and
the vehicle running condition, so that the vehicle will follow the
preceding vehicle. This system enables the vehicle to predict its running
condition before the actual control result of the preceding vehicle is
obtained. Thus, the vehicle can smoothly follow the preceding vehicle
without an extensive control delay.
However, the foregoing prior art is prone to the following problem. Assume
that three or more vehicles run in a platoon and that a second vehicle
simply follows a first vehicle on the basis of data from the first
vehicle, and a third vehicle follows the second vehicle on the basis of
data from the second vehicle, and so on. In this situation, it may be
difficult to appropriately control a vehicle if, for example, a vehicle
running immediately in front of the vehicle leaves the platoon. For
example, if the first vehicle leaves the platoon, the second vehicle has
to function as a leading vehicle and must shift its operation from a
follower mode to an auto-driving mode. On the other hand, if the second
vehicle leaves the platoon, the third vehicle may continue running in the
follower mode because the first vehicle now serves as a leading vehicle.
Thus, if it is possible to appropriately change vehicle running mode based
on the position of the vehicle within a platoon, a more flexible and
adaptable control operation can be realized. However, such a feature has
not been considered in the prior art.
SUMMARY OF THE INVENTION
The present invention is intended to overcome the foregoing problem of the
prior art, and provides a platoon running control system which recognizes
a position of a vehicle within a platoon and appropriately controls the
vehicle according to its position, even when there is a change in the
platoon.
In order to accomplish the foregoing object of the invention, there is
provided a platoon running control system, installed on a vehicle,
comprising: a receiving portion for receiving data transmitted from a
preceding vehicle; a transmitting portion for transmitting data to a
following vehicle; an identification code setting portion for assigning to
the vehicle an identification code indicative of a leading vehicle if the
receiving portion has not received data, and an identification code
obtained by converting the identification code of the preceding vehicle
contained in the received data according to a predetermined rule if the
receiving portion has received the data; and a control portion for
controlling running of the vehicle based on the identification code
assigned to the vehicle by the identification code setting portion. The
identification code indicates the position of this controlled vehicle
within the platoon, and is used to appropriately control the vehicle
depending on its position within the platoon.
Although the identification code indicative of the leading vehicle may be
set to any number, 1 is particularly preferable. The predetermined rule
may be optimally set as follows:
ID of the vehicle=ID of the preceding vehicle+1
Such a rule is preferable because this makes the ID of the leading vehicle
1, the ID of the second vehicle in the platoon 2, the ID of the third 3,
etc. As such, the identification codes can indicate respective positions
of vehicles within the platoon.
When the ID of the vehicle is not the ID indicative of the leading vehicle,
the control section controls the running operation of the vehicle based on
the running data from the preceding vehicle, so that platoon running can
be reliably operated. In this case, the vehicle control does not
necessarily depend only on the data from the preceding vehicle. For
example, it is possible to use additional data, such as on-road data
detected by a sensor installed on the vehicle.
On the other hand, when the ID of the vehicle is the ID indicative of the
leading vehicle, it in effect means that the vehicle is running as a head
of the platoon. However, the vehicle may be assigned the ID indicative of
the leading vehicle, in cases where the vehicle was the third vehicle in
the platoon and the second vehicle has left the platoon. This is because,
in this situation, the vehicle cannot receive data from the preceding
vehicle. Therefore, even if the vehicle has the ID indicative of the
leading vehicle, the vehicle may be controlled so that it accelerates and
catches up with (moves close to) a currently preceding vehicle, when the
previous ID of the vehicle indicates that it was the third vehicle.
Further, if the vehicle wishes to leave the platoon, it transmits such
information to the following vehicle, which then receives the information.
This process ensures a reliable control operation. Specifically, if the
vehicle receives platoon-leaving information from the vehicle ahead, the
vehicle recognizes that it will soon be unable to receive data from the
preceding vehicle and then changes its ID to an ID indicative of the
leading vehicle. The determination as to whether or not the preceding
vehicle was the leading vehicle can be made based on the previous ID of
the vehicle. For example, if the previous ID of the vehicle indicates that
it was the third running vehicle of the platoon, the preceding vehicle
which has left the platoon was not the leading vehicle. In this case, the
vehicle still has another preceding vehicle, and operates an acceleration
control to catch up with the preceding vehicle.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more apparent from the following detailed
description of a presently preferred embodiment when taken in conjunction
with the accompanying drawings.
FIG. 1 is a schematic view showing the configuration of a platoon running
control system according to the present invention.
FIG. 2 is a block diagram showing the configuration of the platoon running
control system shown in FIG. 1.
FIG. 3 is a flowchart showing operations of a vehicle control ECU and a
communication control ECU.
FIG. 4 is a continuation of the flowchart shown in FIG. 3.
DESCRIPTION OF THE A PREFERRED EMBODIMENT
Referring to FIG. 1, a vehicle to which the present invention is applied
includes, at its front end, a magnetic sensor 10 for detecting magnetism
generated from magnetic markers 100 placed on a road surface. The magnetic
intensity detected by the magnetic sensor 10 is used to determine the
position of the vehicle on the road, that is, a lateral displacement of
the vehicle from the center of the road. The vehicle also includes at its
inner upper portion a CCD camera 12 for photographing a scene in front of
the vehicle, such as a preceding vehicle or the like. The captured image
is then processed and used for controlling the vehicle when it follows a
preceding vehicle or when it runs by auto-driving operation. A light
receiver 14 is disposed adjacent to the CCD camera 12 and receives light
(optical) data transmitted from the preceding vehicle. Data
reception/transmission is not limited to light. Infrared rays, ultrasonic
waves, millimeter waves and microwaves are also preferable as a desired
data transmission means. A detection signal from the magnetic sensor 10
and an image signal from the CCD camera 12 are supplied to a vehicle
control ECU located at the center of the vehicle. The vehicle control ECU
16 is composed of a microcomputer, and controls the operation of the
vehicle according to an identification code (ID), which will be described
later. Specifically, the vehicle control ECU 16 activates a steering
actuator 18 based on the detection signal supplied from the magnetic
sensor 10 or activates the steering actuator 18, a brake actuator 20, or a
throttle actuator 21 based on the running data of the preceding vehicle
received by the light receiver 14. The data received by the light receiver
14 is supplied to a communication control ECU 22. Further, a light
transmitter 24 is provided at the rear portion of the vehicle so as to
transmit data to a following vehicle. The communication control ECU 22
controls the data to be transmitted from the light transmitter 24 and the
timing of such data transmission. The communication control ECU 22, which
is also composed of a microcomputer, transmits and receives data to and
from the vehicle control ECU 16. The communication control ECU 22 also
processes identification codes on the basis of the data concerning the
preceding vehicle transmitted from the light receiver 14, as will be
described later. Specifically, the communication control ECU 22 assigns an
identification code ID to the vehicle while transmitting the
identification code ID and platoon-leaving information to the following
vehicle.
In this embodiment, a communication system at the time of platoon running
is preferably a narrow band communication system in which information from
the preceding vehicle is transmitted only to the controlled vehicle. The
communication may be limited to only one direction, that is, from the
preceding vehicle to the vehicle following it. The information to be
transmitted includes an identification code ID of the vehicle, a speed of
the vehicle, an acceleration and deceleration, a steering angle, a brake
actuation/release signal, and a special notice to the following vehicle.
The ID is useful when each vehicle in the platoon recognizes its position
therein. The vehicle speed, acceleration/deceleration, steering angle and
so on are effective in controlling running of the following vehicle in the
platoon. The special notice is effective in informing the following
vehicle that the controlled vehicle is about to leave the platoon, or that
it is about to merge in the platoon.
The platoon running of this embodiment is carried out using the foregoing
system configuration. The basic algorithm of this platoon running is as
follows:
(1) All the vehicles in auto-drive operation are supposed to participate in
the platoon running when predetermined conditions are met.
(2) In the first place, all the vehicles in the auto-driving have an
identification code ID=1 indicating that each vehicle is a leading
vehicle, and transmit the ID backward.
(3) When a vehicle receives data from a preceding vehicle, the vehicle
changes its ID according to the following rule:
ID of the vehicle=ID of the preceding vehicle+1.
Further, a message indicating such an ID change is provided as a special
notice.
For example, when the controlled vehicle is in auto-driving and moves
within a predetermined distance from the preceding vehicle, the preceding
vehicle transmits data ID=1 to the controlled vehicle. Then, the ID of the
vehicle is changed to ID=2. The communication control ECU 22 of the
vehicle transmits the data ID=2 to the following vehicle. The vehicle
control ECU 16 of the following vehicle changes its ID to ID=3. In this
way, each vehicle in the platoon is provided with each ID indicative of
its position within the platoon.
Referring to the flowcharts of FIGS. 3 and 4, the operation sequences of
the vehicle control ECU 16 and the communication control ECU 22 will be
described in detail.
First, when an operator inputs a certain operation command, the vehicle
control ECU 16 determines whether or not the input command is related to
starting auto-drive operation (steps S101, S102, S111). If it is the
auto-drive operation start command, the vehicle control ECU 16 sets an
auto-drive mode (step S112). In the auto-drive mode, as described above,
the magnetic sensor 10 detects the magnetic markers 100 and calculates the
lateral displacement of the vehicle. The steering actuator 18, the brake
actuator 20, and the throttle actuator 21 are controlled so as to regulate
vehicle speed. Alternatively, white lines defining a lane where the
vehicle runs may be detected from the picture captured by the CCD camera
12 in order to control the steering angle of the vehicle along the white
lines.
After the auto-drive mode is set, it is determined whether or not the
communication control ECU 22 has received data from the vehicle control
ECU 16 (step S104). If the communication control ECU 22 has received such
data, it is then determined whether or not the vehicle is set to a
platoon-leaving mode (step S115). (In order to leave the platoon, the
driver sets the platoon-leaving mode. Then, the vehicle control ECU 16
shifts the vehicle operation mode to the platoon-leaving mode; this mode
will be described in more detail later.) If the vehicle is not set to
platoon-leaving mode, but remains in auto-drive mode, the communication
control ECU 22 determines whether or not data has been received from the
preceding vehicle (step S116). The data from the preceding vehicle is
first received by the light receiver 14 and then transmitted to the
communication control ECU 22. The absence of data from the preceding
vehicle represents that the controlled vehicle is running alone or is a
leading vehicle. In this state, the ID=1 indicative of a leading vehicle
is assigned to the vehicle (step S124). It is further determined whether
or not a compulsory ID change flag has been set (step S125). The
compulsory ID change flag is set when the preceding vehicle informs it
will leave the platoon; this will be described in detail later.
On the other hand, if data from the preceding vehicle has been received in
step S116, this means that the vehicle follows the preceding vehicle.
Then, the vehicle receives a new ID, i.e. ID of the preceding vehicle+1
(step S117).
It is then determined, at step S118, whether or not the present ID=1 and
the previous ID.gtoreq.3. For example, if the vehicle was a second vehicle
within the platoon and the preceding vehicle left the platoon, the ID of
the vehicle is changed from ID=2 to ID=1 at step S124, and the previous ID
is determined to be less than 3. On the other hand, if the vehicle was a
third vehicle within the platoon and the preceding vehicle left the
platoon, the ID of the vehicle is changed from ID=3 to ID=1 at step S124,
and the previous ID is recognized as being 3 or greater. When the previous
ID of the vehicle is recognized as being 3 or more, that is, if the
vehicle was in the third or succeeding position within the platoon and the
preceding vehicle left the platoon, this means that the vehicle has now at
least one preceding vehicle. In this case, an acceleration command is
supplied to the vehicle control ECU 15, which then controls the vehicle to
catch up with the preceding vehicle (step S119). On the contrary, if the
previous ID is less than 3, the vehicle is now a leading vehicle, so that
the foregoing control operation will not be performed.
The ID of the vehicle increases when the vehicle participates in the
platoon and now follows the preceding vehicle. On the contrary, the ID of
the vehicle decreases when the preceding vehicle has left the platoon. In
either case, the following vehicle may be affected, i.e., the ID of the
following vehicle will soon be changed. Therefore, in order to inform the
following vehicle of this, the communication control ECU 22 adds a special
notice including an ID change message and so on to transmission data (step
S120). Here, the special notice also includes platoon-leaving information
of the controlled vehicle and of the preceding vehicle. It is further
determined whether or not the data received from the preceding vehicle
contain the special notice (step S121). If the data contain the special
notice, the special notice is encoded and added to the vehicle's
transmission data (step S122). Then, this special notice is transmitted to
the following vehicle along with the vehicle running data, (step S123). In
this way, when the controlled vehicle receives the platoon-leaving
information from the preceding vehicle, the information is transmitted to
the following vehicle. Therefore, not only the running data of the
controlled vehicle but also information on the preceding vehicle are
transmitted to the following vehicle. Thus, the following vehicle can
recognize the platoon running state and smoothly continue platoon running.
As described, if the controlled vehicle is the leading vehicle, it is
assigned ID=1. On the other hand, if the vehicle follows the preceding
vehicle within the platoon, it is assigned an ID according to its position
within the platoon. If the vehicle is assigned the ID and receives data
from the preceding vehicle, the data is transmitted to the vehicle control
ECU so as to continue platoon running (steps S104, S105, S108).
Specifically, data from the preceding vehicle contains running data such
as the vehicle speed, acceleration/deceleration, steering angle, and ID.
The vehicle control ECU 16 calculates a control amount based on the
running data and activates the steering actuator 18, the brake actuator
22, and so on. During platoon running, it is preferable to control
vehicle-to-vehicle distance and vehicle speed using data from the magnetic
sensor 10 and the CCD camera 12 as well as the data from the preceding
vehicle. For example, it is preferable to set a ratio of the data from the
preceding vehicle to the road data, including the data from the magnetic
sensor, to 4:6.
If the data from the preceding vehicle includes one or more special notice,
they are stored in a memory (step S109). When the vehicle transmits data
to the following vehicle, the stored special notice is checked as
described above (step S121), and then is transmitted to the following
vehicle.
When the controlled vehicle, which has the ID, does not receive any data
from a preceding vehicle, this is checked a predetermined number of times
(for example, 5), and it is further determined whether or not the vehicle
has received a special notice of platoon-leaving from the preceding
vehicle (step S106). If such a special notice of platoon-leaving is stored
in memory, it means that the vehicle cannot receive data because the
preceding vehicle has left the platoon. Then, the compulsory ID change
flag is set as a preparation for change of the vehicle's ID (step S107).
As already described, when this flag is set, it is recognized that the ID
of the vehicle has been changed to ID=1 because of the absence of a
preceding vehicle (see step S125). Then, the control process advances to
step S118. Specifically, if the vehicle was running in the third or
succeeding position in the platoon before the preceding vehicle left the
platoon, a command is provided to the vehicle control ECU 22 so as to
accelerate the vehicle and continue platoon running. On the other hand, if
the vehicle was second within the platoon, the vehicle is controlled to
start auto-driving.
In addition to a case where the preceding vehicle leaves the platoon during
platoon running, it is also conceivable that the controlled vehicle itself
leaves the platoon. In this case, the driver of the vehicle inputs the
platoon-leaving mode. Therefore, YES is determined at steps S102 and NO is
determined at step S111 and the vehicle control ECU 16 changes operation
mode to platoon-leaving mode (steps S113, S114). In this mode, the vehicle
control ECU 16 drives the steering actuator 18 so that the vehicle will
move to another lane. Before platoon-leaving is completed, the vehicle
control ECU 16 adds a platoon-leaving code to the vehicle data as special
notice, and transmits it to the following vehicle (steps S126, S127,
S123). If platoon-leaving is completed, data transmission is terminated
because there is no following vehicle (step S128). The completion of
platoon-leaving may be determined, for example, based on whether or not
the steering angle of the vehicle does not change by more than a
predetermined amount. Further, in order to leave the platoon, the operator
may manually operate the steering wheel, instead of automatic steering
operation.
In the foregoing embodiment, the vehicle is provided with an ID=1 if it is
the leading vehicle within the platoon. The vehicle is provided with an ID
indicative of its position within the platoon if it follows a preceding
vehicle. It is thus possible to definitely identify the position of the
vehicle within the platoon. Therefore, if the preceding vehicle leaves the
platoon, the vehicle can determine whether or not to resume platoon
running based on the ID change in the vehicle itself. In this manner, the
running of the vehicles can be appropriately controlled depending upon
existing situations. Further, the following vehicles are notified if the
preceding vehicle, or the controlled vehicle itself, leaves the platoon.
Thus, the vehicles in the platoon can advantageously respond quickly and
appropriately to a change of the platoon.
In this embodiment, if the data from the preceding vehicle contains
platoon-leaving information, the controlled vehicle sets a compulsory ID
change flag, and changes its ID to 1. Specifically, if the vehicle does
not receive any more data from the preceding vehicle, or after the
preceding vehicle has started to leave the platoon, the vehicle sets the
compulsory flag. However, since the reception of platoon-leaving
information from the preceding vehicle means that there will soon be no
preceding vehicle, the vehicle may run at a fixed speed, or slightly
decelerate and then run at the decelerated speed. Alternatively, it is
also possible to sequentially shift from a platoon running control mode
based on data from the preceding vehicle to the auto-driving mode. For
example, in the platoon running mode, the ratio of the data from the
preceding vehicle to the data from the magnetic sensor and so on is 4:6,
as described above. However, when the vehicle receives platoon-leaving
information, such a ratio may be changed to 2:8 so as to smoothly shift
the operation mode to auto-driving.
The foregoing platoon-leaving operation is also applicable to a case where
another vehicle merges into the platoon. The merged vehicle receives data
from the preceding vehicle, and changes its ID from ID=1 to a new ID
indicative of its position within the platoon after the merger according
to the rule, ID=ID of the preceding vehicle+1. The merged vehicle then
transmits the ID and also a special notice indicating its merger to the
following vehicle. The following vehicle receives this special notice and
transmits it to the next following vehicle, at the same time, adding 1 to
its own ID. Alternatively, the light receiver 14 may receive information
from a road beacon indicative of the presence of a merging vehicle and the
vehicle control ECU 16 may be controlled to increase the distance between
the vehicle and the preceding vehicle, so that the merging vehicle can
join the platoon smoothly.
The platoon running control system of the invention enables each vehicle
running within a platoon to recognize its position within the platoon, and
can appropriately control the vehicle, even when there is a change in the
platoon, according to the vehicle running states. It is thus possible to
smoothly and rapidly re-form the platoon, even when a vehicle has left the
platoon and the platoon becomes discontinuous.
While there have been described what is at present considered to be
preferred embodiments of the invention, it will be understood that various
modification may be made thereto, and it is intended that the appended
claims cover all such modifications as fall within the true spirit and
scope of the invention.
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